以數位控制太陽光電系統之類比數位 轉換器及數位脈波寬度調節器設計

A/D Converter and Digital PWM Designs for Digital Controlled Photovoltaic Power Systems

李昀桓(Yun-Huan Li)

指導教授 ： 黃柏鈞

國立清華大學/電機資訊學院/電機工程學系/碩士(2013年)

摘要

在石油燃料及天然氣的價格逐漸升高，對替代能源的需求也日益增加。太陽能被視為下一代之主流能源，其應用亦被廣泛討論。然而，如何更有效率地提升太陽能轉換效率也成為重要議題。為了提升在太陽能光電系統在受到遮蔽時的輸出功率，我們使用分散式太陽能光電系統之架構，並且搭配最大功率追蹤功能，使每一塊太陽能板都能操作在其最大功率輸出點。內部的數位訊號處理器包含了最大功率追蹤以及電流預測之功能。此外，本實驗亦提供介面電路作為類比環境及數位環境之溝通橋樑。本論文將會著重在討論介面電路包含類比數位轉換器以及數位脈波寬度調節器之設計。
在介面電路當中包含了8 位元之逐步漸進式類比數位轉換器，並且針對降低內部切換功率及降低所使用電容面積大小做了精確的設計。在逐步漸進操作上使用了非同步操作方式以達到降低其所需要的操作速度及控制電路之功率消耗。
另一方面，混和式數位脈波寬度調變器提供二個頻道同時控制直流升壓轉換器之上橋及下橋之開關。在同步開關的切換式轉換電路的實現上，加入空白時間以避免上下橋開關同時導通產生瞬間電路短路造成漏電流，使得轉換效率降低。此混和式數位脈波寬度調變器亦包含了矯正電路抵抗製程偏移所造成的影響，並且配有自動重啟功能，降低整體功率消耗。
本實驗使用TSMC 0.25-μm HV CMOS 1P3M 製程當中的2.5V 元件實現，晶片大小為1.7mm × 1.9mm，並且成功的操作在分散式太陽能光電系統平台上。

關鍵字

類比數位 轉換器 ； 數位脈波寬度調節器 ； 數位控制 ； 太陽光電系統

並列摘要

As oil and gas prices have risen, the demand for alternative energy sources also increased. Photovoltaic (PV), the third important renewable energy has been widely discussed; however, how to transfer solar energy efficiently has become the top issue. In order to deal with the performance degradation caused by sunlight blocking, we used a distributed panel photovoltaic power conversion system, which utilizes maximum power point tracking (MPPT) algorithm to achieve the optimal power conversion rate when being deployed individually on each panel. An internal digital signal processor (DSP) is used to implement MPPT algorithm and predict current to regulate DC/DC boost converter. Moreover, an interface for connecting analog environment and digital control logic is also required. This thesis will mainly focus on designing this interface circuit, which includes an analog to digital converter (A/D Converter) and a digital pulse width modulation (digital PWM).
A successive approximation analog to digital converter (SA-ADC) with 8-bit resolution is used in this circuit. The circuit structure is specifically designed for saving the switching energy and plate area of capacitor. The successive approximation algorithm is controlled asynchronously for reducing the power being consumed by clock generator and control circuits.
This digital pulse width modulator (digital PWM) provides two control channels for switching high-side and low-side switches of DC/DC boost converter. The leakage of this boost converter is effectively suppressed by tuning the dead time between switches. This digital PWM is accompanied with calibration circuit to overcome the process variation and self-rest circuit to lower the power consumption.
This interface circuit was fabricated by TSMC 0.25μm HV CMOS 1P3M process, and 2.5V devices among this process are used. This chip area is 1.7mm×1.9mm, and has been verified in a real PV power conversion prototype.

並列關鍵字

ADC ； DPWM ； Digital Controller ； PV system

參考文獻

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